A 2.4-mile swim, a 112-mile bike ride, and a casual 26.2-mile marathon to boot. These are the constituent parts of the Ironman triathlon, the event which Hannah Nicklin promised herself at 28 that she would complete by the age of 30. And this is the story of how she got there.

But Equations for a Moving Body – written and performed by Nicklin – doesn’t just speak to the sporting types among us (admittedly almost certainly a low turnout at an arts festival); it’s a story of unshakeable endurance, of the psychology behind what makes our mind and body continue in the face of extremity, and of those who help us along the way.

On a stage dressed only with a water bottle, a laptop and projected memories, Alexander Kelly’s direction is sensitive and stylistically in tune with the subject matter. Nicklin’s spoken tone is tailored to the minutes, miles and measures of her activities, rising and falling, quickening and slowing the pace on the edges of semi-spoken word as she takes us through the rigorous stages of training. Yet it’s her modestly intelligent and endearingly awkward nature that glues me to her words, smile and square-framed glasses.

Nicklin uses live internet to translate storytelling to modern terms, providing a welcomed spontaneity. Online articles, documentary footage, Facebook, Flickr and fitness apps visually track her progress, recording her achievements in relation to her fellow sportspeople.

This format is its most affecting upon a period of silence in which Nicklin Googles the death of John, a runner and friend. Revealing a fatal ski accident, she calculates and counts down the time it took for John to fall to his death, using the equation for a falling body and a beaming selfie. We are given a raw life insight, despite the hindered authenticity of the purple already-clicked-on links, apparent because of daily performances.

Part TED Talk, part theatrical performance and all-reality, Equations for a Moving Body thrives in its educational nuances. Nicklin’s sporting explanations shed a sensitive light and shade, working to freshen her pacing. It’s a compelling format but, within the attention wavering running time of an hour and a half, it still takes a sportsman to feel absolutely moved and completely captivated by this piece.

I haven’t really been following the Olympics in Rio. It feels a world away from the saturated bubble of the Fringe. But after watching Hannah’s story, I went home and tuned in on the TV. Despite feeling a little underwhelmed by my own non gold medal-winning life, I watch brimming with the empowerment that comes with sharing in the sheer determination of others.

Equations for a Moving Body is playing at The Northern Stage, Summerhall until August 27.